Using Drosophila as a model to understand TDP-43 function in ALS

使用果蝇作为模型来了解 TDP-43 在 ALS 中的功能

• 批准号: 8110887
• 负责人: DAVID B MORTON
• 金额: $ 21.75万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-02-01 至 2013-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8110887
• 关键词: Adult; Affect; Alzheimer' s Disease; Amyotrophic Lateral Sclerosis; Anatomy; Animals; Biological Models; C-terminal; Cell Death; Cell Nucleus; Characteristics; Cheese; Code; Cytoplasm; Cytoplasmic Inclusion; Data; Defect; Dementia; Development; Disease; Drosophila genus; Drosophila melanogaster; Functional disorder; Future; Gene Proteins; Genes; Genetic; Goals; Human; Investigation; Larva; Lead; Link; Location; Mediating; Modeling; Molecular; Motor; Motor Neuron Disease; Motor Neurons; Mutation; Names; Nature; Nerve Degeneration; Nervous system structure; Neuroanatomy; Neurodegenerative Disorders; Neurons; Parkinson Disease; Pathology; Pathway interactions; Patients; Phenotype; Physiological; Physiology; Predisposition; Process; Property; Protein Isoforms; Proteins; Publishing; RNA-Binding Proteins; Research; Role; Sampling; Speed; System; Testing; Therapeutic; Tissues; Toxic effect; age related; base; drug development; fly; loss of function; motor deficit; mutant; neuron loss; neuropathy target esterase; null mutation; protein TDP-43; protein aggregate; protein function; research study; response; therapy design; therapy development; tool

DESCRIPTION (provided by applicant): Amyotrophic lateral sclerosis (ALS) is a devastating disease affecting about 2 in 100,000 people in the USA each year. Recent discoveries have the potential to dramatically change our understanding of the causes of ALS and identification of possible targets for treatment. ALS results from the selective loss of motor neurons, which in ALS patients contain cytoplasmic aggregates of proteins. Identification that a major constituent of these aggregates is the RNA-binding protein TDP-43, which is normally localized in the nucleus, has opened up many new directions in ALS research. A large number of mutations in TDP-43 have also been identified in ALS patients providing a causative link between this protein and the disease. TDP-43 aggregates have also been identified in post-mortem samples of patients who have died of other neurodegenerative diseases such as fronto-temporal dementias, Alzheimer's and Parkinson's diseases, suggesting that TDP-43 pathology might be a causative agent in a wide variety of diseases. It is critical to understand how TDP-43 dysfunction leads to disease. Two possible mechanisms have been proposed. The first is that the TDP-43 aggregates are inherently toxic and lead to motor neuron cell death. The second model, which is not mutually exclusive with the first, is that the loss of normally functioning protein in the nucleus is the proximate cause of motor neuron disruption. We are using the fruit fly, Drosophila melanogaster, as a model to understand the function of TDP- 43 in neurons and the consequences of aberrant expression. Null mutations in the Drosophila orthologue of TDP-43, named TBPH, are pupal lethal and show larval motor defects. Over-expression of any of three naturally occurring isoforms of TBPH in all tissues is early larval lethal. When expression is restricted to motor neurons, both larvae and adult flies have motor deficits. The bulk of the TDP-43 mutations in ALS are found in the C-terminal domain and our data shows that the C-terminal domain of TBPH is necessary for maximum toxicity. The primary goals of this application are to determine the cellular and molecular mechanisms underlying these defects. We have identified a genetic interaction between TBPH/TDP-43 and another neurodegeneration gene, named swiss cheese (sws), which suggests that sws is required for the toxic properties of TDP-43. This interaction is particularly intriguing because mutations in the human orthologue of sws, named neuropathy target esterase, lead to motor neuron disease. In addition to testing our hypothesis that the toxic effects of over-expressed TDP-43 result from an interaction between TDP-43 and sws we also propose to examine the anatomical and electrophysiological phenotypes of motor neurons that over-express TDP-43 in wild-type and sws mutant backgrounds. Any therapeutic approaches to treat ALS that rely on targeting TDP-43 dysfunction require an understanding of the molecular mechanisms that underlie the toxic effects of TDP-43. Using the powerful genetic tools available in Drosophila will greatly accelerate this understanding. PUBLIC HEALTH RELEVANCE: The first step in developing therapies for ALS is to identify the genes/proteins that either directly cause ALS or confer susceptibility to develop ALS in response to environmental triggers. Recent discoveries that strongly link TDP-43 to ALS suggest that this is a possible future target. Any therapeutic approaches to treat ALS that rely on targeting TDP-43 dysfunction require an understanding of the molecular mechanisms that underlie the toxic effects of TDP-43. This application focuses on understanding the mechanisms that lead to neurodegeneration by TDP-43 dysfunction using the fruit fly, Drosophila melanogaster as a model, an approach that will greatly speed up the process of designing therapies targeting TDP-43.

描述（由申请人提供）：肌萎缩侧索硬化症 (ALS) 是一种毁灭性的疾病，每年影响美国 100,000 人中约 2 人。最近的发现有可能极大地改变我们对 ALS 病因的理解，并确定可能的治疗目标。 ALS 是运动神经元选择性丧失的结果，ALS 患者的运动神经元含有蛋白质的细胞质聚集物。这些聚集体的主要成分是 RNA 结合蛋白 TDP-43（通常位于细胞核中），这一发现为 ALS 研究开辟了许多新方向。在 ALS 患者中也发现了 TDP-43 的大量突变，这表明该蛋白与该疾病之间存在因果关系。在死于其他神经退行性疾病（例如额颞叶痴呆、阿尔茨海默病和帕金森病）的患者的尸检样本中也发现了 TDP-43 聚集体，这表明 TDP-43 病理学可能是多种神经退行性疾病的致病因素。疾病。了解 TDP-43 功能障碍如何导致疾病至关重要。已经提出了两种可能的机制。首先，TDP-43 聚集体具有固有毒性，会导致运动神经元细胞死亡。第二种模型与第一种模型并不相互排斥，即细胞核中正常功能蛋白质的丧失是运动神经元破坏的直接原因。我们使用果蝇 Drosophila melanogaster 作为模型来了解 TDP-43 在神经元中的功能以及异常表达的后果。果蝇 TDP-43 的直系同源物（称为 TBPH）的无效突变是蛹致死的，并表现出幼虫运动缺陷。所有组织中三种天然存在的 TBPH 亚型中任何一种的过度表达都会导致早期幼虫死亡。当表达仅限于运动神经元时，幼虫和成蝇都会出现运动缺陷。 ALS 中的大部分 TDP-43 突变存在于 C 端结构域中，我们的数据表明 TBPH 的 C 端结构域对于最大毒性是必需的。该应用的主要目标是确定这些缺陷背后的细胞和分子机制。我们已经确定了 TBPH/TDP-43 与另一种名为瑞士奶酪 (sws) 的神经退行性基因之间的遗传相互作用，这表明 sws 是 TDP-43 毒性特性所必需的。这种相互作用特别有趣，因为 sws 的人类直系同源物（称为神经病靶酯酶）的突变会导致运动神经元疾病。除了测试我们的假设，即过度表达的 TDP-43 的毒性作用是由 TDP-43 和 sws 之间的相互作用引起的，我们还建议检查野生动物中过度表达 TDP-43 的运动神经元的解剖学和电生理学表型。类型和SWS突变体背景。任何依赖于 TDP-43 功能障碍的 ALS 治疗方法都需要了解 TDP-43 毒性作用的分子机制。使用果蝇中可用的强大遗传工具将大大加速这种理解。 公共卫生相关性：开发 ALS 疗法的第一步是确定直接导致 ALS 或因环境触发因素而导致 ALS 易感性的基因/蛋白质。最近的发现将 TDP-43 与 ALS 密切相关，表明这是未来可能的目标。任何依赖于 TDP-43 功能障碍的 ALS 治疗方法都需要了解 TDP-43 毒性作用的分子机制。该应用重点以果蝇、黑腹果蝇为模型，了解 TDP-43 功能障碍导致神经变性的机制，这种方法将大大加快针对 TDP-43 的疗法的设计过程。